Middlesex County
Massachusetts — Natural Disaster Risk Assessment
HighComposite Risk Score
National percentile: 97th
Middlesex County faces high composite natural disaster risk (NRI Risk Index score 96.9, 97th national percentile), driven primarily by ice storm and riverine flood exposure. Expected annual loss across all 18 hazard types is $322M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Ice Storm | Very High | 2.70 / yr | $8M |
| Riverine Flood | High | 4.25 / yr | $224M |
| Lightning | High | 21.62 / yr | $3M |
| Earthquake | Medium | 0.00 / yr | $24M |
| Heat Wave | Medium | 5.70 / yr | $9M |
| Hurricane | High | 0.16 / yr | $30M |
| Strong Wind | High | 0.97 / yr | $3M |
| Cold Wave | High | 1.85 / yr | $9M |
| Tornado | Medium | 0.18 / yr | $9M |
| Drought | Medium | 7.12 / yr | $2M |
| Wildfire | Low | 0.00 / yr | $268K |
| Winter Weather | Medium | 17.15 / yr | $147K |
| Coastal Flood | Low | 6.16 / yr | $418K |
| Landslide | Very Low | 0.55 / yr | $2K |
| Hail | Very Low | 2.30 / yr | $107K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Frequently Asked Questions
What is the overall natural disaster risk for Middlesex County?
Middlesex County has a composite FEMA National Risk Index score of 96.9 out of 100, placing it in the High category and the 97th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Middlesex County?
The three highest-rated hazards are Ice Storm (Very High, $8M EAL), Riverine Flood (High, $224M EAL), Lightning (High, $3M EAL). These account for most of the county's expected annual losses.
How does Middlesex County compare to other Massachusetts counties?
Middlesex County ranks #1 of 14 Massachusetts counties for overall natural disaster risk, with a high rating.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Middlesex County's $322M EAL is a statistical average, not a guarantee for any specific year or address.